1. Field of the Invention
This invention relates to lubricants containing an antimicrobial compound.
2. Brief Description of the Prior Art
Lubricants containing an antimicrobial compound have been generally known. Commonly, such lubricants include an antimicrobial compound for one or more of a number of reasons, including preservation of the lubricant from deterioration or contamination, and protection of those coming in contact with the lubricant from a condition known as contact dermatitis. For these and similar reasons for the use of an antimicrobial compound, the antimicrobial compound must be active in the presence of the lubricant's substituents and strong enough to perform the function for which it is used. In the typical instances of preserving the lubricant or preventing contact dermatitis, the antimicrobial compounds heretofore proposed for use have been toxic to humans if ingested. Consequently, antimicrobial compound--containing lubricants have been limited to certain applications in which human ingestion is unlikely because they are too aggressive for human ingestion.
Moreover, certain applications for lubricants require the use of a special class of lubricants called boundary lubricants. Such applications often pose moderate to severe loading, high speed, or moderate to high temperature conditions that non-boundary lubricants cannot adequately tolerate. Consequently, extreme pressure (EP) additives have been developed that, when added to a base lubricant, produce a boundary lubricant for these severe applications. The presence of EP additives in lubricants is very important if a lubricant is to perform favorably under heavily loaded, high speed, or high temperature conditions. Typical of such an application are dental tools such as dental hand pieces, and some medical devices as well as food, pharmaceutical and cosmetics manufacturing, processing or packaging equipment, where boundary lubrication is essential in cage/ball and cage/race bearing contacts, bushings, slides, cams, gears etc. In the absence of a suitable boundary lubricant, such devices wear out much too soon because metal to metal contact and/or metal to ceramic contact, and/or metal to other composite material contact, and/or composite material to composite material contact creates unacceptable wear and surface distress.
Dental tools and some medical devices as well as food, pharmaceutical, and cosmetic manufacturing processing or packaging equipment, in which use of a boundary lubricant would be highly desirable, are designed and/or required to come into contact with the human body and/or it's internal parts or have a high probability of incidental contact with the body or food/pharmaceutical products that are ingested. However, extreme pressure additives used in boundary lubricants are so highly toxic that they are unsuitable for use in devices that may come into contact with the human body and/or it's internal parts, including the oral cavity in the case of dental tools or food/pharmaceutical machinery in the case of incidental product contact that may be ingested. Furthermore, known antimicrobial compounds used in lubricants are also too aggressive for such uses.